Neurotoxic reactive astrocytes are induced by activated microglia

Deciphering the spectrum of astrocyte diversity: Insights into molecular, morphological, and functional dimensions in health and neurodegenerative diseases

Astrocytes are the most abundant and morphologically complex glial cells that play active roles in the central nervous system (CNS). Recent research has identified shared and region-specific astrocytic genes and functions, elucidated the cellular origins of their regional diversity, and uncovered the molecular networks for astrocyte morphology, which are essential for their functional complexity. Reactive astrocytes exhibit a wide range of functional diversity in a context-specific manner in CNS disorders. This review discusses recent advances in understanding the molecular and morphological diversity of astrocytes in healthy individuals and those with neurodegenerative diseases, such as Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis.

Morphological diversification and functional maturation of human astrocytes in glia-enriched cortical organoid transplanted in mouse brain

Astrocytes, the most abundant glial cell type in the brain, are underrepresented in traditional cortical organoid models due to the delayed onset of cortical gliogenesis. Here we introduce a new glia-enriched cortical organoid model that exhibits accelerated astrogliogenesis. We demonstrated that induction of a gliogenic switch in a subset of progenitors enabled the rapid derivation of astroglial cells, which account for 25-31% of the cell population within 8-10 weeks of differentiation. Intracerebral transplantation of these organoids reliably generated a diverse repertoire of cortical neurons and anatomical subclasses of human astrocytes. Spatial transcriptome profiling identified layer-specific expression patterns among distinct subclasses of astrocytes within organoid transplants. Using an in vivo acute neuroinflammation model, we identified a subpopulation of astrocytes that rapidly activates pro-inflammatory pathways upon cytokine stimulation. Additionally, we demonstrated that CD38 signaling has a crucial role in mediating metabolic and mitochondrial stress in reactive astrocytes. This model provides a robust platform for investigating human astrocyte function.

TREM1-Microglia crosstalk: Neurocognitive disorders

Neurocognitive Disorders (NCDs) primarily affect cognitive functions, including learning, memory, perception, and problem-solving. They predominantly arise as pathological sequelae of central nervous system (CNS) disorders. Emerging evidence suggests that microglial inflammatory activation within the hippocampus underlies the pathogenesis of cognitive impairment. Triggering receptor expressed on myeloid cells 1 (TREM1), a pattern-recognition receptor on microglia, becomes upregulated in response to injury and synergistically amplifies inflammatory responses mediated by other pattern-recognition receptors, leading to uncontrolled inflammation. While TREM1 is lowly expressed in the resting state, its upregulation upon exposure to injurious inflammatory stimuli promotes microglial activation and contributes to the development of NCDs. Consequently, TREM1 may serve as a critical receptor in microglia-mediated inflammation. This article reviews the current understanding of TREM1 and its role in NCDs pathogenesis.

The IL-33/ST2 Axis Protects Retinal Ganglion Cells by Modulating the Astrocyte Response After Optic Nerve Injury

IL-33 and its receptor ST2 play crucial roles in tissue repair and homeostasis. However, their involvement in optic neuropathy due to trauma and glaucoma remains unclear. Here, we report that IL-33 and ST2 were highly expressed in the mouse optic nerve and retina. Deletion of IL-33 or ST2 exacerbated retinal ganglion cell (RGC) loss, retinal thinning, and nerve fiber degeneration following optic nerve (ON) injury. This heightened retinal neurodegeneration correlated with increased neurotoxic astrocytes in Il33-/- mice. In vitro, rIL-33 mitigated the neurotoxic astrocyte phenotype and reduced the expression of pro-inflammatory factors, thereby alleviating the RGC death induced by neurotoxic astrocyte-conditioned medium in retinal explants. Exogenous IL-33 treatment improved RGC survival in Il33-/- and WT mice after ON injury, but not in ST2-/- mice. Our findings highlight the role of the IL-33/ST2 axis in modulating reactive astrocyte function and providing neuroprotection for RGCs following ON injury.

(Re)building the nervous system: A review of neuron-glia interactions from development to disease

Neuron-glia interactions are fundamental to the development and function of the nervous system. During development, glia, including astrocytes, microglia, and oligodendrocytes, influence neuronal differentiation and migration, synapse formation and refinement, and myelination. In the mature brain, glia are crucial for maintaining neural homeostasis, modulating synaptic activity, and supporting metabolic functions. Neurons, inherently vulnerable to various stressors, rely on glia for protection and repair. However, glia, in their reactive state, can also promote neuronal damage, which contributes to neurodegenerative and neuropsychiatric diseases. Understanding the dual role of glia-as both protectors and potential aggressors-sheds light on their complex contributions to disease etiology and pathology. By appropriately modulating glial activity, it may be possible to mitigate neurodegeneration and restore neuronal function. In this review, which originated from the International Society for Neurochemistry (ISN) Advanced School in 2019 held in Montreal, Canada, we first describe the critical importance of glia in the development and maintenance of a healthy nervous system as well as their contributions to neuronal damage and neurological disorders. We then discuss potential strategies to modulate glial activity during disease to protect and promote a properly functioning nervous system. We propose that targeting glial cells presents a promising therapeutic avenue for rebuilding the nervous system.

C3/C3aR Bridges Spinal Astrocyte-Microglia Crosstalk and Accelerates Neuroinflammation in Morphine-Tolerant Rats

AIMS

Communication within glial cells acts as a pivotal intermediary factor in modulating neuroimmune pathology. Meanwhile, an increasing awareness has emerged regarding the detrimental role of glial cells and neuroinflammation in morphine tolerance (MT). This study investigated the influence of crosstalk between astrocyte and microglia on the evolution of morphine tolerance.

METHODS

Sprague-Dawley rats were intrathecally treated with morphine twice daily for 9 days to establish morphine-tolerant rat model. Tail-flick latency test was performed to identify the analgesic effect of morphine. The role of microglia, astrocyte and C3-C3aR axis in morphine tolerance were elucidated by real-time quantitative polymerase chain reaction, Western blot, and immunofluorescence.

RESULTS

Chronic morphine treatment notably promoted the activation of microglia, upregulated the production of proinflammatory mediators (interleukin-1 alpha (IL-1α), tumor necrosis factor alpha (TNFα), and complement component 1q (C1q)). Simultaneously, it programed astrocytes to a pro-inflammatory phenotype (A1), which mainly expresses complement 3 (C3) and serping1. PLX3397 (a colony-stimulating factor 1 receptor (CSF1R) inhibitor), Compstain (a C3 inhibitor) and SB290157(a C3aR antagonist) could reverse the above pathological process and alleviate morphine tolerance to different extents.

CONCLUSION

Our findings identify C3-C3aR axis as an amplifier of microglia-astrocyte crosstalk, neuroinflammation and a node for therapeutic intervention in morphine tolerance.

Role of Regulatory T Cells in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a common cerebrovascular disease that can lead to severe neurological dysfunction in surviving patients, resulting in a heavy burden on patients and their families. When ICH occurs, the blood‒brain barrier is disrupted, thereby promoting immune cell migration into damaged brain tissue. As important immunosuppressive T cells, regulatory T (Treg) cells are involved in the maintenance of immune homeostasis and the suppression of immune responses after ICH. Treg cells mitigate brain tissue damage after ICH in a variety of ways, such as inhibiting the neuroinflammatory response, protecting against blood‒brain barrier damage, reducing oxidative stress damage and promoting nerve repair. In this review, we discuss the changes in Treg cells in ICH clinical patients and experimental animals, the mechanisms by which Treg cells regulate ICH and treatments targeting Treg cells in ICH, aiming to support new therapeutic strategies for clinical treatment.

Fasting the brain for mental health

Unfavorable socioeconomic and geopolitical conditions such as poverty, violence and inequality increase vulnerability to mental disorders. Also, exposure to a poor nutrition such as high-energy dense (HED) diets has been linked to alterations in brain function, leading to anxiety, addiction, and depression. HED diets rich in saturated fatty acids or obesity can activate the innate immune system in the brain, especially microglia, increasing proinflammatory cytokines such as interleukin 1 beta (IL1-β) and interleukin 6 (IL-6), in part, by the stimulation of toll-like receptor 4 (TLR4) and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Intermittent fasting (IF), an eating protocol characterized by alternating periods of fasting with periods of eating, has gained recognition as a weight-management strategy to reduce obesity. Accordingly, during IF inflammation and brain function can be modulated by production of ketone bodies and modulation of the intestinal microbiota, which also promote the induction of brain-derived neurotrophic factor (BDNF), which is involved in neurogenesis and neuronal plasticity. Although IF has contributed to reduce body weight and improve metabolic profiles, its influence on mental health remains an evolving field of research. Here, we provide experimental evidence supporting the role of IF reducing neuroinflammation as a valuable approach to improve mental health.

Application of Adipose Extracellular Matrix and Reduced Graphene Oxide Nanocomposites for Spinal Cord Injury Repair

Graphene-based materials (GBMs) hold strong promise to restore the spinal cord microenvironment and promote functional recovery after spinal cord injury (SCI). Nanocomposites consisting of reduced graphene oxide (rGO) and adipose tissue-derived extracellular matrix (adECM) are known to promote neuronal growth in vitro and to evoke a biocompatible response in vivo when implanted on top of the intact spinal cord. In this study, pristine adECM and adECM-rGO nanocomposites are implanted directly after hemisection SCI in rats. Scaffolds composed of collagen type I (COL) are applied as negative control, based on evidence that COL triggers integrin-mediated astrogliosis. However, COL scaffolds induce orthotopic bone formation in the lesion site and are therefore excluded from further analyses. Compared to pristine adECM, adECM-rGO nanocomposites completely restore spinal cord integrity. Macrophage-mediated uptake and clearance of rGO remnants is observed as early as 3 weeks post-implantation. Nanocomposites show an elevated presence of βIII-tubulin-positive axons in the host-material interface after 8 weeks, yet scaffold penetration by axons is only occasionally observed. This is partially due to an increased expression of chondroitin sulfate proteoglycans (CSPGs) within the nanocomposites, even though reactive astrogliosis is unaltered. Despite the complete restoration of tissue architecture, adECM-rGO treatment does not significantly improve functional recovery.

Long-term characterisation of the relationship between change in depression severity and change in inflammatory markers following inflammation-stratified treatment with vortioxetine augmented with celecoxib or placebo

BACKGROUND

Major depressive disorder (MDD) is a highly prevalent condition with a substantial incidence of relapse or treatment resistance. A subset of patients show evidence of low-grade inflammation, with these patients having a higher likelihood of more severe or difficult to treat courses of illness. Anti-inflammatory treatment of MDD has been investigated with mixed results, and no known studies have included assessments beyond cessation of the anti-inflammatory agent, meaning it remains unknown if any benefit from treatment persists. The objective of the present study was to investigate treatment outcomes up to 29 weeks post-cessation of celecoxib or placebo augmentation of an antidepressant, and how concentrations of selected inflammatory markers change over the same period.

METHODS

The PREDDICT parallel-group, randomised, double-blind, placebo-controlled trial (University of Adelaide, Australia) ran from December 2017 to April 2020. Participants with MDD were stratified into normal range or elevated inflammation strata according to screening concentrations of high sensitivity C-reactive protein (hsCRP). Participants were randomised to treatment with vortioxetine and celecoxib or vortioxetine and placebo for six weeks, and vortioxetine alone for an additional 29 weeks (35 total weeks). Following a previous publication of results from the six-week RCT phase, exploratory analyses were performed on Montgomery-Åsberg Depression Rating Scale (MADRS) scores, response and remission outcomes, and selected peripheral inflammatory markers across the entire study duration up to week 35.

RESULTS

Participants retained at each observation were baseline N=119, week 2 N=115, week 4 N=103, week 6 N=104, week 8 N=98, week 22 N=81, and week 35 N=60. Those in the elevated hsCRP celecoxib-augmented group had a statistically significantly greater reduction in MADRS score from baseline to week 35 compared to all other groups, demonstrating the greatest clinical improvement long-term, despite no group or strata differences at preceding time points. Response and remission outcomes did not differ by treatment group or hsCRP strata at any time point. Changes in hsCRP between baseline and week 35 and Tumour Necrosis Factor-α (TNF-α) concentrations between baseline and week 6 and baseline and week 35 were statistically significantly associated with MADRS scores observed at week 6 and week 35 respectively, with reducing TNF-α concentrations associated with reducing MADRS scores and vice versa in each case. A post-hoc stratification of the participant cohort by baseline TNF-α concentrations led to significant prediction by the derived strata on clinical response at weeks 6, 8 and 35, with participants with elevated baseline TNF-α less likely to achieve clinical response.

INTERPRETATION

The present analysis suggests for the first time a possible longer-term clinical benefit of celecoxib augmentation of vortioxetine in inflammation-associated MDD treatment. However, further research is needed to confirm the finding and to ascertain the reason for such a delayed effect. Furthermore, the trial suggests that TNF-α may have a stronger relationship with anti-inflammatory MDD treatment outcomes than hsCRP, and should be investigated further for potential predictive utility.

CLINICAL TRIALS REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000527369p. Registered on 11 April 2017, http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12617000527369p.

Pericyte ablation causes hypoactivity and reactive gliosis in adult mice

Capillary pericytes are important regulators of cerebral blood flow, blood-brain barrier integrity and neuroinflammation, but can become lost or dysfunctional in disease. The consequences of pericyte loss or dysfunction is extremely difficult to discern when it forms one component of a complex disease process. To evaluate this directly, we examined the effect of adult pericyte loss on mouse voluntary movement and motor function, and physiological responses such as hypoxia, blood-brain barrier (BBB) integrity and glial reactivity. Tamoxifen delivery to Pdgfrβ-CreERT2:: Rosa26-DTA transgenic mice was titrated to produce a dose-dependent ablation of pericytes in vivo. 100mg/kg of tamoxifen ablated approximately half of all brain pericytes, while two consecutive daily doses of 300mg/kg tamoxifen ablated >80% of brain pericytes. In the open field test, mice with ∼50% pericyte loss spent more time immobile and travelled half the distance of control mice. Mice with >80% pericyte ablation also slipped more frequently while performing the beam walk task. Our histopathological analyses of the brain revealed that blood vessel density was unchanged, but vessel lumen width was increased. Pericyte-ablated mice also exhibited: mild BBB disruption; increased neuronal hypoxia; astrogliosis and increased IBA1+ immunoreactivity, suggestive of microgliosis and/or macrophage infiltration. Our results highlight the importance of pericytes in the brain, as pericyte loss can directly compromise brain health and induce behavioural alterations in mice.

Severity of Repetitive Mild Traumatic Brain Injury Depends on Microglial Heme Oxygenase-1 and Carbon Monoxide

Traumatic brain injury is one of the most common cerebral incidences worldwide. Repetitive mild traumatic brain injuries occurring, for example, in athletes or victims of abuse, can cause chronic neurodegeneration due to neuroinflammation, in which the crosstalk between reactive astrocytes and activated microglia is crucial for modulating neuronal damage. The inducible enzyme heme oxygenase-1 and its product carbon monoxide are known to be ascribed neuroprotective and anti-inflammatory properties. We caused repetitive mild traumatic brain injuries in wild-type mice compared to mice without microglial heme oxygenase-1 expression. Additionally, mice were treated daily with either air or carbon monoxide exogenously. In wild-type mice, we observed enhanced microglia activation and astrogliosis as well as vasodilation after repetitive trauma. In heme oxygenase-1 knockout mice, we observed enhanced activation of microglia and astrocytes at baseline pretrauma with a lack of an adequate inflammatory response to repetitive injury. However, the knockout led to enhanced NF-κB and IFNγ expression in the post-trauma period. Carbon monoxide exerted neuroprotection, as suggested by reduced wake-up times in mice and by beneficially altering inflammation post-traumatic brain injury. This study further underlines the crucial role of the heme oxygenase-1/carbon monoxide system in the modulation of neuronal damage and the associated neuroinflammatory response after repetitive traumatic brain injury.

α-Synuclein pathology as a target in neurodegenerative diseases

α-Synuclein misfolds into pathological forms that lead to various neurodegenerative diseases known collectively as α-synucleinopathies. In this Review, we provide a comprehensive overview of pivotal advances in α-synuclein research. We examine structural features and physiological functions of α-synuclein and summarize current insights into key post-translational modifications, such as nitration, phosphorylation, ubiquitination, sumoylation and truncation, considering their contributions to neurodegeneration. We also highlight the existence of disease-specific α-synuclein strains and their mechanisms of pathological spread, and discuss seed amplification assays and PET tracers as emerging diagnostic tools for detecting pathological α-synuclein in clinical settings. We also discuss α-synuclein aggregation and clearance mechanisms, and review cell-autonomous and non-cell-autonomous processes that contribute to neuronal death, including the roles of adaptive and innate immunity in α-synuclein-driven neurodegeneration. Finally, we highlight promising therapeutic approaches that target pathological α-synuclein and provide insights into emerging areas of research.

Effects of Muse Cell on a Mouse Model With Acute Encephalopathy

INTRODUCTION

Acute encephalopathy (AE) in childhood due to a viral infection causes convulsions and altered consciousness, leading to severe sequelae and death. Among the four types of AE, cytokine storm-induced AE is the most severe and causes serious damage to the brain. Moreover, a fundamental treatment for AE has not been established yet. Recently, it has been shown that the administration of multilineage-differentiating stress-enduring (Muse) cells, a population of mesenchymal stem cells, improves symptoms in various types of brain injuries when administered in the subacute phase (1-7 days after brain damage). We aimed to examine the effects of Muse cells in a cytokine storm-induced AE animal model using immunocompromised nonobese diabetic/severe combined immunodeficiency (NOD/SCID) neonatal mice.

METHODS

We established a modified protocol to induce AE-like symptoms in NOD/SCID. Then, Muse cells were injected at an acute phase (2-4 h after hyperthermia treatment).

RESULTS

Injection of Muse cells significantly improved body weight gain 1 day after treatment and the survival ratio for 3 weeks.

CONCLUSION

These effects could be a result of the direct and/or indirect upregulation of IL-10, an anti-inflammatory cytokine, in the Muse cell-treated brain. Although non-Muse cells, a residual cell population in the bone marrow after isolating Muse cells, also improved some symptoms, their effects were weaker than those of Muse cells. Our results indicate that the injection of Muse cells in the acute phase has an effect on AE, suggesting that they exert their therapeutic effects not only in the subacute phase but also in the acute phase.

DJ-1 regulates astrocyte activation through miR-155/SHP-1 signaling in cerebral ischemia/reperfusion injury

Reactive astrocyte activation in the context of cerebral ischemia/reperfusion (I/R) injury gives rise to two distinct subtypes: the neurotoxic A1 type and the neuroprotective A2 type. DJ-1 (Parkinson disease protein 7, PARK7), originally identified as a Parkinson's disease-associated protein, is a multifunctional anti-oxidative stress protein with molecular chaperone and signaling functions. SHP-1 (Src homology 2 domain-containing phosphatase-1) is a protein tyrosine phosphatase closely associated with cellular signal transduction. miR-155 is a microRNA that participates in cellular functions by regulating gene expression. Recent studies have uncovered the relationship between DJ-1 and astrocyte-mediated neuroprotection, which may be related to its antioxidant properties and regulation of signaling molecules such as SHP-1. Furthermore, miR-155 may exert its effects by influencing SHP-1, providing a potential perspective for understanding the molecular mechanisms of stroke. A middle cerebral artery occlusion/reperfusion (MCAO/R) model and an oxygen-glucose deprivation/reperfusion (OGD/R) model were established to simulate focal cerebral I/R injury in vivo and in vitro, respectively. The in vivo interaction between DJ-1 and SHP-1 has been experimentally validated through immunoprecipitation. Overexpression of DJ-1 attenuates I/R injury and suppresses miR-155 expression. In addition, inhibition of miR-155 upregulates SHP-1 expression and modulates astrocyte activation phenotype. These findings suggest that DJ-1 mediates astrocyte activation via the miR-155/SHP-1 pathway, playing a pivotal role in the pathogenesis of cerebral ischemia-reperfusion injury. Our results provide a potential way for exploring the pathogenesis of ischemic stroke and present promising targets for pharmacological intervention.

Mitochondrial-targeted therapies in traumatic brain injury: From bench to bedside

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide, with limited effective therapeutic options currently available. Recent research has highlighted the pivotal role of mitochondrial dysfunction in the pathophysiology of TBI, making mitochondria an attractive target for therapeutic intervention. This review comprehensively examines advancements in mitochondrial-targeted therapies for TBI, bridging the gap from basic research to clinical applications. We discuss the underlying mechanisms of mitochondrial damage in TBI, including oxidative stress, impaired bioenergetics, mitochondrial dynamics, and apoptotic pathways. Furthermore, we highlight the complex interplay between mitochondrial dysfunction, inflammation, and blood-brain barrier (BBB) integrity, elucidating how these interactions exacerbate injury and impede recovery. We also evaluate various preclinical studies exploring pharmacological agents, gene therapy, and novel drug delivery systems designed to protect and restore mitochondrial function. Clinical trials and their outcomes are assessed to evaluate the translational potential of mitochondrial-targeted therapies in TBI. By integrating findings from bench to bedside, this review emphasizes promising therapeutic avenues and addresses remaining challenges. It also provides guidance for future research to pave the way for innovative treatments that improve patient outcomes in TBI.

Immune cell infiltration and modulation of the blood-brain barrier in a guinea pig model of tuberculosis: Observations without evidence of bacterial dissemination to the brain

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) infection, is a chronic inflammatory disease. Although typically associated with inflammation of the lungs and other peripheral tissues, increasing evidence has uncovered neurological consequences attributable to Mtb infection. These include deficits in memory and cognition, increased risk for neurodegenerative disease, and progressive neuropathology. Although the neurological effects of the disease, without CNS infection, have been characterized, the mechanism of neurotoxicity is unknown. We hypothesized that alterations to the blood-brain barrier (BBB) allows peripheral immune cells to enter the brain, initiating a neuroinflammatory response. To test this hypothesis, guinea pigs were exposed by aerosol to a laboratory and a clinical Mtb strain for 15 days. Following Mtb infection, proteins critical to BBB function, including claudin V and collagen IV, are modulated without evidence of bacterial dissemination to the brain. This is correlated with increased contact of astrocytic processes to vessels in the brain, as well as increased expression of the water channel protein aquaporin 4 (AQP4) on endfeet. Upon further investigation, we discovered the potential role of glial reactivity, which is increased following infection with both bacterial strains, in the progression of BBB changes and, ultimately, the permeability of peripheral immune cells into the brain. Through these data, we have obtained a preliminary understanding of the mechanisms of cellular stress in the brain following pulmonary Mtb infection which should be further investigated in future studies.

Major ozonated autohemotherapy promoted functional recovery following spinal cord injury in adult rats via the inhibition of oxidative stress and inflammation

This study sought to explore the value of major ozonated autohemotherapy (MOA) as a treatment for spinal cord injury (SCI) in a rat model system. In total, 54 female Sprague-Dawley rats were randomized into sham-operated, SCI model, and MOA treatment groups. We found that relative to the SCI model group, rats that underwent MOA treatment exhibited improved locomotor scores on days 14, 21, and 28 after injury (p < 0.05) together with reduced residual urine on days 5, 7, 14, and 21 after injury (p < 0.05). MOA treatment also lowered proinflammatory TNF-α, IL-1α, and C1q levels on day 3 post-injury (p < 0.05), decreased malondialdehyde levels, and enhanced superoxide dismutase activity (p < 0.001). Activated astrocytes in MOA-treated rats exhibited larger soma and higher levels of extracellular matrix secretion, whereas reactive microglia in the MOA group presented with a ramified morphology in contrast to the amoeboid morphology exhibited by these cells in SCI model rats. MOA offers potential value as a means of protecting spinal cord integrity, potentially through anti-inflammatory, antioxidant, and regulatory effects that shape the polarization of astrocytes and microglia.

Xixin Decoction May Treat Vascular Dementia by Modulating the NPTX2/C1q/C3 Complement Pathway

Vascular dementia (VaD) is a type of dementia that results from brain injury caused by cerebrovascular disease or vascular risk factors. Accumulating evidence from clinical studies has found that Xixin decoction can effectively improve the cognitive function of patients with VaD and improve their daily living ability. However, the pathogenesis of VaD is not fully understood, and the therapeutic mechanism of Xixin decoction is also unclear. The Morris water maze, new object recognition, transmission electron microscopy observation, Golgi staining, Nissl staining, Western blotting, and quantitative real-time polymerase chain reaction were employed to explore the therapeutic mechanism of Xixin decoction. The results showed decreased learning and cognitive abilities, hippocampal neuron damage, decreased NPTX2 protein expression, and increased expression of inflammatory factors such as C1q and C3 in the model group compared with the control group. Furthermore, compared with the model group, the above symptoms were improved after administration of Xixin decoction, and the activity of the NPTX2/C1q/C3 complement pathway was altered. In conclusion, these results suggested that Xixin decoction might treat VaD by modulating the NPTX2/C1q/C3 complement pathway.

Astrocyte-derived MFG-E8 facilitates microglial synapse elimination in Alzheimer's disease mouse models

Region-specific synapse loss is an early pathological hallmark in Alzheimer's disease (AD). Emerging data in mice and humans highlight microglia, the brain-resident macrophages, as cellular mediators of synapse loss; however, the upstream modulators of microglia-synapse engulfment remain elusive. Here, we report a distinct subset of astrocytes, which are glial cells essential for maintaining synapse homeostasis, appearing in a region-specific manner with age and amyloidosis at onset of synapse loss. These astrocytes are distinguished by their peri-synaptic processes which are 'bulbous' in morphology, contain accumulated p62-immunoreactive bodies, and have reduced territorial domains, resulting in a decrease of astrocyte-synapse coverage. Using integrated in vitro and in vivo approaches, we show that astrocytes upregulate and secrete phagocytic modulator, milk fat globule-EGF factor 8 (MFG-E8), which is sufficient and necessary for promoting microglia-synapse engulfment in their local milieu. Finally, we show that knocking down Mfge8 specifically from astrocytes using a viral CRISPR-saCas9 system prevents microglia-synapse engulfment and ameliorates synapse loss in two independent amyloidosis mouse models of AD. Altogether, our findings highlight astrocyte-microglia crosstalk in determining synapse fate in amyloid models and nominate astrocytic MFGE8 as a potential target to ameliorate synapse loss during the earliest stages of AD.

Mechanisms and Emerging Regulators of Neuroinflammation: Exploring New Therapeutic Strategies for Neurological Disorders

Neuroinflammation is a complex and dynamic response of the central nervous system (CNS) to injury, infection, and disease. While acute neuroinflammation plays a protective role by facilitating pathogen clearance and tissue repair, chronic and dysregulated inflammation contributes significantly to the progression of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis. This review explores the cellular and molecular mechanisms underlying neuroinflammation, focusing on the roles of microglia, astrocytes, and peripheral immune cells. Key signaling pathways, including NF-κB, JAK-STAT, and the NLRP3 inflammasome, are discussed alongside emerging regulators such as non-coding RNAs, epigenetic modifications, and the gut-brain axis. The therapeutic landscape is evolving, with traditional anti-inflammatory drugs like NSAIDs and corticosteroids offering limited efficacy in chronic conditions. Immunomodulators, gene and RNA-based therapeutics, and stem cell methods have all shown promise for more specific and effective interventions. Additionally, the modulation of metabolic states and gut microbiota has emerged as a novel strategy to regulate neuroinflammation. Despite significant progress, challenges remain in translating these findings into clinically viable therapies. Future studies should concentrate on integrated, interdisciplinary methods to reduce chronic neuroinflammation and slowing the progression of neurodegenerative disorders, providing opportunities for revolutionary advances in CNS therapies.

Advances in mesenchymal stem cell-centered stem cell therapy in the treatment of hypoxic-ischemic injury

Hypoxic-ischemic brain damage (HIBD) is a leading cause of neonatal death and neurological dysfunction for which no particularly effective treatment is available. Stem cells possess multi-directional differentiation potential and can secrete a variety of cytokines. They not only have the ability to replace tissue and repair lesions but also improve neurological damage caused by HIBD through paracrine mechanisms, including anti-apoptosis, reduction of inflammation, and promotion of endogenous repair. Recently, as research on stem cells, particularly mesenchymal stem cells, has deepened, the application of stem cells in treating HIBD has become a prominent research topic, yielding fruitful results, particularly regarding the neuroprotective effects and mechanisms of the stem cell paracrine pathway. With advances in stem cell injection, distribution, and biomaterial incorporation, applications of stem cells have become more widespread and comprehensive. This review summarizes and discusses the research progress on stem cells in HIBD treatment to provide theoretical support for HIBD treatment and enhance the feasibility of clinical translation.

The Role of Neuroglia in the Development and Progression of Schizophrenia

Schizophrenia is a complex heterogenous disorder thought to be caused by interactions between genetic and environmental factors. The theories developed to explain the etiology of schizophrenia have focused largely on the dysfunction of neurotransmitters such as dopamine, serotonin and glutamate with their receptors, although research in the past several decades has indicated strongly that other factors are also involved and that the role of neuroglial cells in psychotic disorders including schizophrenia should be given more attention. Although glia were originally thought to be present in the brain only to support neurons in a physical, metabolic and nutritional capacity, it has become apparent that these cells have a variety of important physiological roles and that abnormalities in their function may make significant contributions to the symptoms of schizophrenia. In the present paper, we review the interactions of brain microglia, astrocytes and oligodendroglia with aspects such as transmitter dysregulation, neuro-inflammation, oxidative stress, synaptic function, the gut microbiome, myelination and the blood-brain barrier that appear to affect the cause, development and treatment of schizophrenia. We also review crosstalk between microglia, astrocytes and oligodendrocytes and the effects of antipsychotics on neuroglia. Problems associated with studies on specific biomarkers for glia in schizophrenia are discussed.

Inflammasomes in neurodegenerative diseases

Inflammasomes represent a crucial component of the innate immune system, which respond to threats by recognizing different molecules. These are known as pathogen-associated molecular patterns (PAMPs) or host-derived damage-associated molecular patterns (DAMPs). In neurodegenerative diseases and neuroinflammation, the accumulation of misfolded proteins, such as beta-amyloid and alpha-synuclein, can lead to inflammasome activation, resulting in the release of interleukin (IL)-1β and IL-18. This activation also induces pyroptosis, the release of inflammatory mediators, and exacerbates neuroinflammation. Increasing evidence suggests that inflammasomes play a pivotal role in neurodegenerative diseases. Therefore, elucidating and investigating the activation and regulation of inflammasomes in these diseases is of paramount importance. This review is primarily focused on evidence indicating that inflammasomes are activated through the canonical pathway in these diseases. Inflammasomes as potential targets for treating neurodegenerative diseases are also discussed.

Radiation-Induced Brain Injury: Mechanistic Insights and the Promise of Gut-Brain Axis Therapies

Radiation therapy is widely recognized as an efficacious modality for treating neoplasms located within the craniofacial region. Nevertheless, this approach is not devoid of risks, predominantly concerning potential harm to the neural structures. Adverse effects may encompass focal cerebral necrosis, cognitive function compromise, cerebrovascular pathology, spinal cord injury, and detriment to the neural fibers constituting the brachial plexus. With increasing survival rates among oncology patients, evaluating post-treatment quality of life has become crucial in assessing the benefits of radiation therapy. Consequently, it is imperative to investigate therapeutic strategies to mitigate cerebral complications from radiation exposure. Current management of radiation-induced cerebral damage involves corticosteroids and bevacizumab, with preclinical research on antioxidants and thalidomide. Despite these efforts, an optimal treatment remains elusive. Recent studies suggest the gut microbiota's involvement in neurologic pathologies. This review aims to discuss the causes and existing treatments for radiation-induced cerebral injury and explore gut microbiota modulation as a potential therapeutic strategy.

Glucocorticoid-Dependent Retinal Degeneration and Vision Impairment in Mice Susceptible to Prenatal Stress-Induced Behavioral Abnormalities

Chronic exposure to prenatal stress can impair neurogenesis and lead to irreversible cognitive and neuropsychiatric abnormalities in offspring. The retina is part of the nervous system; however, the impacts of prenatal stress on retinal neurogenesis and visual function remain unclear. This study examined how elevated prenatal glucocorticoid levels differentially affect retinal development in the offspring of pregnant mice exposed to chronic unpredictable mild stress (CUMS). Offspring were classified into control, stress-resilient, and stress-susceptible groups based on behavioral tests assessing spatial memory and depression-like behaviors. The stress-susceptible group exhibited significantly altered synaptogenesis, reduced ganglion cell development, decreased retinal thickness, and visiual impairment. These mice also showed a pervasive transformation of retinal astrocytes into a proinflammatory A1-like reactive state, evidenced by increased GFAP and decreased STAT3 expression levels. This astrocyte phenotype shift coincided with disruptions in neurogenesis and synaptic formation. Furthermore, prenatal exposure to exogenous corticosterone confirmed that the effects of prenatal stress are mediated by glucocorticoid-induced retinal neurodegeneration. Our findings suggest that elevated prenatal glucocorticoid levels trigger a series of neurodevelopmental disturbances leading to retinal neurodegeneration and vision impairment. This research highlights the impact of prenatal stress on retinal development and visual health, suggesting new avenues for understanding and potentially mitigating the negative effects of early-life stress on neurodevelopment.

Mapping the current trends and hotspots of extracellular vesicles in Alzheimer's disease: a bibliometric analysis

Background

Extracellular vesicles (EVs) have garnered significant attention in Alzheimer's disease (AD) research over the past decade, largely due to their potential in diagnostics and therapeutics. Although the investigation of EVs in AD is a relatively recent endeavor, a comprehensive bibliometric analysis of this rapidly growing field has yet to be conducted.

Methods

This study aims to elucidate and synthesize the relationship between EVs and AD, offering critical insights to guide future research and expand therapeutic possibilities. Over the past 10-15 years, substantial progress has been made in this domain. Through bibliometric techniques, this analysis assesses research performance by examining scientific publications and metrics, including productivity indicators, impact measurements, data mining, and visualization tools.

Results

A total of 602 publications were analyzed using various online platforms for bibliometric analysis. Notably, the number of publications began to increase rapidly in 2018, with China and the United States emerging as leaders in this research area. The National Institute on Aging produced the highest number of publications among institutions. The Journal of Molecular Sciences and the Journal of Biological Chemistry were the most prolific and most frequently cited journals, respectively. Among individual contributors, Dimitrios Kapogiannis was identified as the most productive author, while Edward J. Goetzl was the most co-cited. The most prevalent keywords included "neurodegenerative diseases," "exosomes," "blood biomarkers," "amyloid beta," "microglia," and "tau protein." Current research hotspots involve microRNA dysregulation, oxidative stress, carboxyl-terminal fragments, small EVs, and mesenchymal stem cell-derived EVs, indicating key areas for future research.

Conclusion

Research on microRNA dysregulation, oxidative stress, carboxyl-terminal fragments, small EVs, and mesenchymal stem cell-derived EVs represents a critical frontier in the study of Alzheimer's disease. The role of EV-mediated neuroinflammation in AD is a focal point of ongoing investigation and will likely shape future developments in the field.

Multimodal single-cell profiling reveals neuronal vulnerability and pathological cell states in focal cortical dysplasia

Focal cortical dysplasia (FCD) is a neurodevelopmental condition characterized by malformations of the cerebral cortex that often cause drug-resistant epilepsy. In this study, we performed multi-omics single-nuclei profiling to map the chromatin accessibility and transcriptome landscapes of FCD type II, generating a comprehensive multimodal single-nuclei dataset comprising 61,525 cells from 11 clinical samples of lesions and controls. Our findings revealed profound chromatin, transcriptomic, and cellular alterations affecting neuronal and glial cells in FCD lesions, including the selective loss of upper-layer excitatory neurons, significant expansion of oligodendrocytes and immature astrocytic populations, and a distinct neuronal subpopulation harboring dysmorphic neurons. Furthermore, we uncovered activated microglia subsets, particularly in FCD IIb cases. This comprehensive study unveils neuronal and glial cell states driving FCD development and epileptogenicity, enhancing our understanding of FCD and offering directions for targeted therapy development.

Protocol for the longitudinal study of neuroinflammation and reactive astrocytes in Lcn2CreERT2 mice

During brain disease, astrocytes can reprogram into a reactive state that alters many of their functions. Here, we present a protocol for studying neuroinflammation and reactive astrogliosis in mice using lipopolysaccharide (LPS) from E. coli. We describe steps for employing the Lcn2CreERT2 mouse crossed into a fluorescent Cre reporter line to label a subset of reactive astrocytes during and after inflammation. We then detail procedures for the longitudinal study of reactive astrocytes during the induction, progression, and/or resolution of astrogliosis. For complete details on the use and execution of this protocol, please refer to Agnew-Svoboda et al.1.

Therapeutic impact of a benzofuran derivative on Aluminium chloride-induced Alzheimer's disease-like neurotoxicity in rats via modulating apoptotic and Insulin 1 genes

Neurodegenerative disorders such as Alzheimer's disease (AD) are age-related and are fatal in advanced cases. There is a limited efficacy of drugs used for the management of these diseases. Herein, the neurotherapeutic efficacy of a benzofuran-derivative-7 (BF-7) was investigated. Aluminum chloride (AlCl3) was employed to induce AD-like brain toxicity in rats. The rats were divided into four groups: Negative control, AlCl3-induced AD rats (100 mg/kg body weight, orally), AlCl3-AD induced rats treated with BF-7 (10 mg/kg body weight, orally), AlCl3-AD-induced rats treated with the standard drug "Donepezil" (10 mg/kg body weight, orally). The behavioral performance was tested using a beam-balance test. Brain and serum acetylcholinesterase (AChE) activities and the brain levels of norepinephrine, dopamine (DA), and serotonin (5-HT) were measured. The genetic expression of Bcl-2, Bax, caspase-3, and insulin 1 were assayed. The histopathological imaging and the immunohistochemical evaluation of Glial Fibrillary Acidic Protein (GFAP) were investigated in the cerebral cortex. Treatment of AD-rats with BF-7 mitigated AlCl3-induced neurotoxicity by improving motor functions, counteracting apoptosis, and exerting cholinergic functions. In addition, the genetic expression of Insulin 1 was upregulated significantly in AD-induced rats treated with BF-7. This compound could be used as a promising candidate for neurotherapeutic drug discovery against AD or any other toxic brain disorders.

Regulation of dynamic spatiotemporal inflammation by nanomaterials in spinal cord injury

Spinal cord injury (SCI) is a common clinical condition of the central nervous system that can lead to sensory and motor impairment below the injury level or permanent loss of function in severe cases. Dynamic spatiotemporal neuroinflammation is vital to neurological recovery, which is collectively constituted by the dynamic changes in a series of inflammatory cells, including microglia, neutrophils, and astrocytes, among others. Immunomodulatory nanomaterials can readily improve the therapeutic effects and simultaneously overcome various drawbacks associated with treatment, such as the off-target side effects and loss of bioactivity of immune agents during circulation. In this review, we discuss the role of dynamic spatiotemporal inflammation in secondary injuries after SCI, elaborate on the mechanism of action and effect of existing nanomaterials in treating SCI, and summarize the mechanism(s) whereby they regulate inflammation. Finally, the challenges and prospects associated with using nanotechnology to modulate immunotherapy are discussed to provide new insights for future treatment. Deciphering the intricate spatiotemporal mechanisms of neuroinflammation in SCI requires further in-depth studies. Therefore, SCI continues to represent a formidable challenge.

Advances in genetically modified neural stem cell therapy for central nervous system injury and neurological diseases

Neural stem cells (NSCs) have increasingly been recognized as the most promising candidates for cell-based therapies for the central nervous system (CNS) injuries, primarily due to their pluripotent differentiation capabilities, as well as their remarkable secretory and homing properties. In recent years, extensive research efforts have been initiated to explore the therapeutic potential of NSC transplantation for CNS injuries, yielding significant advancements. Nevertheless, owing to the formation of adverse microenvironment at post-injury leading to suboptimal survival, differentiation, and integration within the host neural network of transplanted NSCs, NSC-based transplantation therapies often fall short of achieving optimal therapeutic outcomes. To address this challenge, genetic modification has been developed an attractive strategy to improve the outcomes of NSC therapies. This is mainly attributed to its potential to not only enhance the differentiation capacity of NSCs but also to boost a range of biological activities, such as the secretion of bioactive factors, anti-inflammatory effects, anti-apoptotic properties, immunomodulation, antioxidative functions, and angiogenesis. Furthermore, genetic modification empowers NSCs to play a more robust neuroprotective role in the context of nerve injury. In this review, we will provide an overview of recent advances in the roles and mechanisms of NSCs genetically modified with various therapeutic genes in the treatment of neural injuries and neural disorders. Also, an update on current technical parameters suitable for NSC transplantation and functional recovery in clinical studies are summarized.

Tet2-mediated clonal hematopoiesis modestly improves neurological deficits and is associated with inflammation resolution in the subacute phase of experimental stroke

Introduction

Recent work has revealed that clonal hematopoiesis (CH) is associated with a higher risk of numerous age-related diseases, including ischemic stroke, however little is known about whether it influences stroke outcome independent of its widespread effects on cardiovascular disease. Studies suggest that leukocytes carrying CH driver mutations have an enhanced inflammatory profile, which could conceivably exacerbate brain injury after a stroke.

Methods

Using a competitive bone marrow transplant model of Tet2-mediated CH, we tested the hypothesis that CH would lead to a poorer outcome after ischemic stroke by augmenting brain inflammation. Stroke was induced in mice by middle cerebral artery occlusion and neurological outcome was assessed at acute (24 h) and subacute (14 d) timepoints. Brains were collected at both time points for histological, immunofluorescence and gene expression assays.

Results

Unexpectedly, Tet2-mediated CH had no effect on acute stroke outcome but led to a reduction in neurological deficits during the subacute phase. This improved neurological outcome was associated with lower levels of brain inflammation as evidenced by lower transcript levels of various inflammatory molecules alongside reduced astrogliosis.

Discussion

These findings suggest that Tet2-mediated CH may have beneficial effects on outcome after stroke, contrasting with the conventional understanding of CH whereby leukocytes with driver mutations promote disease by exacerbating inflammation.

Electrophysiological Signatures in Global Cerebral Ischemia: Neuroprotection Via Chemogenetic Inhibition of CA1 Pyramidal Neurons in Rats

BACKGROUND

Although there has been limited research into the perturbation of electrophysiological activity in the brain after ischemia, the activity signatures during ischemia and reperfusion remain to be fully elucidated. We aim to comprehensively describe these electrophysiological signatures and interrogate their correlation with ischemic damage during global cerebral ischemia and reperfusion.

METHODS AND RESULTS

We used the 4-vessel occlusion method of inducing global cerebral ischemia in rats. We used in vivo electrophysiological techniques to simultaneously record single units, scalp electroencephalogram, and local field potentials in awake animals. Neuronal damage and astrocyte reactivation were examined by immunofluorescence, immunoblotting, and quantitative real-time reverse-transcription polymerase chain reaction under chemogenetic inhibition of glutamatergic neurons. Electroencephalogram/local field potentials power and phase-amplitude coupling of the theta and low-gamma bands were reduced during ischemia and the acute phase of reperfusion. The firing rate of single units was enhanced by ischemia-reperfusion, and the phase relationship between the local field potentials theta band and neuronal firing was altered. Precise inhibition of hippocampus CA1 pyramidal neuron hyperactivity by chemogenetics rescued the firing dysfunction, ischemic neuronal damage, and A1 astrocyte activation.

CONCLUSIONS

Our results provide a comprehensive description of the characteristics of electrophysiological activity that accompany ischemia-reperfusion and highlight the significance of this activity in ischemic damage.

Regulation of nerve cells and therapeutic potential in central nervous system injury using microglia-derived exosomes

The intercellular communication within the central nervous system (CNS) is of great importance for in maintaining brain function, homeostasis, and CNS regulation. When the equilibrium of CNS is disrupted or injured, microglia are immediately activated and respond to CNS injury. Microglia-derived exosomes are capable of participating in intercellular communication within the CNS by transporting various bioactive substances, including nucleic acids, proteins, lipids, amino acids, and metabolites. Nevertheless, microglia activation is a double-edged sword. Activated microglia can coordinate the neural repair process and, conversely, can amplify tissue injury and impede CNS repair. This work reviewed the roles of exosomes derived from microglia stimulated by different environments (mainly lipopolysaccharide, interleukin-4, and other specific preconditioning) in CNS injury and their possible therapeutic potentials. This work focuses on the regulation of exosomes derived from microglia stimulated by different environments on nerve cells. Meanwhile, we summarized the molecular mechanisms by which the relevant exosomes exert regulatory effects. Exosomes, derived from microglia stimulated by different environments, regulate other nerve cells during the repair of CNS injury, having beneficial or detrimental effects on CNS repair. A comprehensive understanding of the molecular mechanisms underlying their role can provide a robust foundation for the clinical treatment of CNS injury.

An ILK/STAT3 pathway controls glioblastoma stem cell plasticity

Glioblastoma (GBM) is driven by malignant neural stem-like cells that display extensive heterogeneity and phenotypic plasticity, which drive tumor progression and therapeutic resistance. Here, we show that the extracellular matrix-cell adhesion protein integrin-linked kinase (ILK) stimulates phenotypic plasticity and mesenchymal-like, invasive behavior in a murine GBM stem cell model. ILK is required for the interconversion of GBM stem cells between malignancy-associated glial-like states, and its loss produces cells that are unresponsive to multiple cell state transition cues. We further show that an ILK/STAT3 signaling pathway controls the plasticity that enables transition of GBM stem cells to an astrocyte-like state in vitro and in vivo. Finally, we find that ILK expression correlates with expression of STAT3-regulated proteins and protein signatures describing astrocyte-like and mesenchymal states in patient tumors. This work identifies ILK as a pivotal regulator of multiple malignancy-associated GBM phenotypes, including phenotypic plasticity and mesenchymal state.

Astrocytes contribute to toll-like receptor 2-mediated neurodegeneration and alpha-synuclein pathology in a human midbrain Parkinson's model

BACKGROUND

Parkinson's disease (PD) is characterised by degeneration of ventral midbrain dopaminergic (DA) neurons and abnormal deposition of α-synuclein (α-syn) in neurons. Activation of the innate immune pathogen recognition receptor toll-like receptor 2 (TLR2) is associated with exacerbation of α-syn pathology. TLR2 is increased on neurons in the PD brain, and its activation results in the accumulation and propagation of α-syn through autophagy inhibition in neurons. In addition to the aggregation and propagation of pathological α-syn, dysfunction of astrocytes may contribute to DA neuronal death and subsequent clinical progression of PD. However, the role of astrocytes in TLR2-mediated PD pathology is less explored but important to address, given that TLR2 is a potential therapeutic target for PD.

METHODS

Induced pluripotent stem cells from three controls and three PD patients were differentiated into a midbrain model comprised of neurons (including DA neurons) and astrocytes. Cells were treated with or without the TLR2 agonist Pam3CSK4, and α-syn pathology was seeded using pre-formed fibrils. Confocal imaging was used to assess lysosomal function and α-syn pathology in the different cell types, as well as DA neuron health and astrocyte activation.

RESULTS

TLR2 activation acutely impaired the autophagy lysosomal pathway, and potentiated α-syn pathology seeded by pre-formed fibrils in PD neurons and astrocytes, leading to degeneration and loss of DA neurons. The astrocytes displayed impaired chaperone-mediated autophagy reducing their ability to clear accumulated α-syn, and increases of A1 neurotoxic phenotypic proteins SerpinG1, complement C3, PSMB8 and GBP2. Moreover, the phenotypic changes in astrocytes correlated with a specific loss of DA neurons.

CONCLUSIONS

Taken together, these results support a role for astrocyte dysfunction in α-syn accumulation and DA neuronal loss following TLR2 activation in PD.

Microglia-astrocyte crosstalk is regulated by Astragalus polysaccharides mediated through suppression of Sema4D-PlexinB2 signaling in experimental autoimmune encephalomyelitis

The crosstalk between microglia inflamed in multiple sclerosis (MIMS) and astrocytes inflamed in MS (AIMS) is a crucial factor in the formation of the central inflammatory microenvironment and neurotoxicity. Astragalus polysaccharides (APS), an important bioactive component extracted from the dried root of Astragalus, was previously found by our team to attenuate the formation of pro-inflammatory microglia and neurological dysfunction in the experimental autoimmune encephalomyelitis (EAE) mice, a classic model of MS. To investigate the effect of APS on the MIMS-AIMS crosstalk and its underlying mechanism, in this study, a mouse model of EAE and a co-culture model of microglia-astrocytes in vitro were established. It was discovered that APS can alleviate the neurological dysfunction of EAE mice and effectively inhibit the formation of MIMS and AIMS both in vivo and in vitro. Furthermore, it was found that APS can suppress the inflammatory factors of MIMS-AIMS crosstalk in EAE mice and the resulting neurotoxicity in vivo and in vitro. The Sema4D-PlexinB2 signaling is essential for MIMS-AIMS crosstalk and promotes CNS inflammation. We demonstrated that APS can inhibit this signaling in vivo and in vitro. Treatment of recombinant Sema4D protein on cultured astrocytes in vitro significantly increases pro-inflammatory and neurotoxic factors, while APS significantly inhibits them. Conversely, after knockdown of Sema4D expression in microglia, APS no longer improves the neurotoxicity from MIMS-AIMS crosstalk. Overall, these results indicate that APS may modulate MIMS-AIMS crosstalk via the Sema4D-PlexinB2 signaling. This study provides a scientific basis for APS as a potential treatment candidate for demyelinating diseases.

The current research status of the mechanisms and treatment of radioactive brain injury

Radioactive brain injury, a severe complication ensuing from radiotherapy for head and neck malignancies, frequently manifests as cognitive impairment and substantially diminishes patients' quality of life. Despite its profound impact, the pathogenesis of this condition remains inadequately elucidated, and efficacious treatments are notably absent in clinical practice. Consequently, contemporary interventions predominantly focus on symptom alleviation rather than achieving a radical cure or reversing the injury process. This article provides a comprehensive review of the various pathogenic mechanisms and therapeutic strategies associated with radioactive brain injury, offering insights that may guide the development of novel therapeutic strategies.

The Phenotype Changes of Astrocyte During Different Ischemia Conditions

OBJECTIVES

Dementia is becoming a major health problem in the world, and chronic brain ischemia is an established important risk factor in predisposing this disease. Astrocytes, as one major part of the blood-brain barrier (BBB), are activated during chronic cerebral blood flow hypoperfusion. Reactive astrocytes have been classified into phenotype pro-inflammatory type A1 or neuroprotective type A2. However, the specific subtype change of astrocyte and the mechanisms of chronic brain ischemia are still unknown.

METHODS

In order to depict the phenotype changes and their possible roles during this process, a rat bilateral common carotid artery occlusion model (BCAO) was employed in the present study. Meanwhile, the signaling pathways that possibly regulate these changes were investigated as well.

RESULTS

After four-week occlusion, astrocytes in the cortex of BCAO rats were shown to be the A2 phenotype, identified by the significant up-regulation of S100a10 accompanied by the down-regulation of Connexin 43 (CX43) protein. Next, we established in vitro hypoxia models, which were set up by stimulating primary astrocyte cultures from rat cortex with cobalt chloride, low glucose, or/and fibrinogen. Consistent with in vivo data, the cultured astrocytes also transformed into the A2 phenotype with the up-regulation of S100a10 and the down-regulation of CX43. In order to explore the mechanism of CX43 protein changes, C6 astrocyte cells were handled in both hypoxia and low-glucose stimulus, in which decreased pERK and pJNK expression were found.

CONCLUSIONS

In conclusion, our data suggest that in chronic cerebral ischemia conditions, the gradual ischemic insults could promote the transformation of astrocytes into A2 type instead of A1 type, and the phosphorylation of CX43 was negatively regulated by the phosphorylation of ERK and JNK. Also, our data could provide some new evidence of how to leverage the endogenous astrocytes phenotype changes during CNS injury by promoting them to be "protector" and not "culprit".

Pharmacological Inhibition of Astrocytic Transglutaminase 2 Facilitates the Expression of a Neurosupportive Astrocyte Reactive Phenotype in Association with Increased Histone Acetylation

Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury. Recently, it has been demonstrated that ablation of astrocytic transglutaminase 2 (TG2) shifts reactive astrocytes towards a phenotype that improves neuronal injury outcomes both in vitro and in vivo. Additionally, in an in vivo mouse model, pharmacological inhibition of TG2 with the irreversible inhibitor VA4 phenocopied the neurosupportive effects of TG2 deletion in astrocytes. In this study, we extended our comparisons of VA4 treatment and TG2 deletion to provide insights into the mechanisms by which TG2 attenuates neurosupportive astrocytic function after injury. Using a neuron-astrocyte co-culture model, we found that VA4 treatment improves the ability of astrocytes to support neurite outgrowth on an injury-relevant matrix, as we previously showed for astrocytic TG2 deletion. We hypothesize that TG2 mediates its influence on astrocytic phenotype through transcriptional regulation, and our previous RNA sequencing suggests that TG2 is primarily transcriptionally repressive in astrocytes, although it can facilitate both up- and downregulation of gene expression. Therefore, we asked whether VA4 inhibition could alter TG2's interaction with Zbtb7a, a transcription factor that we previously identified as a functionally relevant TG2 nuclear interactor. We found that VA4 significantly decreased the interaction of TG2 and Zbtb7a. Additionally, we assessed the effect of TG2 deletion and VA4 treatment on transcriptionally permissive histone acetylation and found significantly greater acetylation in both experimental groups. Consistent with these findings, our present proteomic analysis further supports the predominant transcriptionally repressive role of TG2 in astrocytes. Our proteomic data additionally unveiled pronounced changes in lipid and antioxidant metabolism in astrocytes with TG2 deletion or inhibition, which likely contribute to the enhanced neurosupportive function of these astrocytes.

Research hotspots and trends on NF-κB in cognitive impairment: a bibliometric analysis

Background

Cognitive impairment (CI) endangers the physical and mental health of patients in a significant manner, and it is expected that the number of people with CI in China will rise to 45.33 million by 2050. Therefore, CI has become a popular research topic. Inflammatory damage plays a key role in the pathogenesis of CI, and NF-κB is an important inflammatory signaling pathway. However, no bibliometric analysis regarding the relationship between CI and NF-κB has been reported.

Methods

A bibliometric analysis regarding NF-κB and CI from 1 January 2008 to 12 December 2023 was conducted in the Science Citation Index-Expanded of the Web of Science Core Collection. The frontiers, hotspots, and trends of research regarding the role of NF-κB in CI were identified. VOSviewer and CiteSpace were used to analyze the retrieved articles and identify the author, country, institution, and keywords, as well as co-cited authors, co-cited journals, and co-cited references.

Results

We analyzed 1,468 original articles and reviews. Publications on NF-κB in CI began in 2010 and increased sharply in 2018. Hong Hao was the most represented author, having published 19 articles, and Chinese authors published more studies than those from other countries. China Pharmaceutical University published the most papers; however, the United States has a strong influence and demonstrates international cooperation. The keywords "apolipoprotein e" and "therapeutic target" demonstrated strong citation bursts, and this tendency may persist in the upcoming years. Neuroinflammation demonstrated a strong influence in research regarding NF-κB in CI. Gut microbiota and ketogenic diet also play an important role in NF-κB in CI.

Conclusion

This bibliometric analysis and visualization using VOSviewer and CiteSpace revealed that the role of NF-κB in CI has become a research hotspot. The results of this study indicated that "neuroinflammation," "microglial," and "pathway" remain hotspots for future research. However, studies regarding NF-κB in CI have predominantly focussed on basic research; future research should include therapeutic targets, microbiota, and ketogenic diet.

Multitarget Effects of Nrf2 Signalling in the Brain: Common and Specific Functions in Different Cell Types

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial regulator of cellular defence mechanisms, essential for maintaining the brain's health. Nrf2 supports mitochondrial function and protects against oxidative damage, which is vital for meeting the brain's substantial energy and antioxidant demands. Furthermore, Nrf2 modulates glial inflammatory responses, playing a pivotal role in preventing neuroinflammation. This review explores these multifaceted functions of Nrf2 within the central nervous system, focusing on its activity across various brain cell types, including neurons, astrocytes, microglia, and oligodendrocytes. Due to the brain's vulnerability to oxidative stress and metabolic challenges, Nrf2 is emerging as a key therapeutic target to enhance resilience against oxidative stress, inflammation, mitochondrial dysfunction, and demyelination, which are central to many neurodegenerative diseases.

Neuroinflammation in Alzheimer disease

Increasing evidence points to a pivotal role of immune processes in the pathogenesis of Alzheimer disease, which is the most prevalent neurodegenerative and dementia-causing disease of our time. Multiple lines of information provided by experimental, epidemiological, neuropathological and genetic studies suggest a pathological role for innate and adaptive immune activation in this disease. Here, we review the cell types and pathological mechanisms involved in disease development as well as the influence of genetics and lifestyle factors. Given the decade-long preclinical stage of Alzheimer disease, these mechanisms and their interactions are driving forces behind the spread and progression of the disease. The identification of treatment opportunities will require a precise understanding of the cells and mechanisms involved as well as a clear definition of their temporal and topographical nature. We will also discuss new therapeutic strategies for targeting neuroinflammation, which are now entering the clinic and showing promise for patients.

Cell surface receptor-mediated signaling in CNS regeneration

Degenerative diseases and injuries of central nervous system (CNS) often cause nerve cell apoptosis and neural dysfunction. Protection of surviving cells or inducing the differentiation of stem cells into functional cells is considered to be an important way of neurorepair. In addition, transdifferentiation technology emerged recently is expected to provide new solutions for nerve regeneration. Cell surface receptors are transmembrane proteins embedded in cytoplasmic membrane, and play crucial roles in maintaining communication between extracellular signals and intracellular signaling processes. The extracellular microenvironment changed dramatically upon neural lesion, exploring the biological function of signals mediated by cell surface receptors will help to develop molecular strategies for nerve regeneration. An increasing number of studies have reported that cell surface receptor-mediated signaling affects the survival, differentiation, and functioning of neural cells, and even regulate their trans-lineage reprogramming. Here, we provide a review on the roles of cell surface receptors in CNS regeneration, thus providing new cues for better treatment of neurodegenerative diseases or nerve injury.

α-linolenic acid mitigates microglia-mediated neuroinflammation of schizophrenia in mice by suppressing the NF-κB/NLRP3 pathway via binding GPR120-β-arrestin 2

BACKGROUND

Schizophrenia (SCZ) is a heterogeneous psychiatric disorder that is poorly treated by current therapies. Emerging evidence indicates that SCZ is closely correlated with a persistent neuroinflammation. α-linolenic acid (ALA) is highly concentrated in the brain and represents a modulator of the immune system by decreasing the inflammatory response in chronic metabolic diseases. This study was first designed to investigate the potential role of dietary ALA on cognitive function and neuroinflammation in mice with SCZ.

METHODS

In vivo, after 2 weeks of modeling, mice were treated with dietary ALA treatment for 6 weeks. In vitro, inflammation model was created using lipopolysaccharide as an inducer in BV2 microglial cells.

RESULTS

Our results demonstrated that ALA alleviated cognitive impairment and enhanced synaptic plasticity in mice with SCZ. Moreover, ALA mitigated systematic and cerebral inflammation through elevating IL-10 and inhibiting IL-1β, IL-6, IL-18 and TNF-α. Furthermore, ALA notably inhibited microglia and pro-inflammatory monocytes, as well as microglial activation andpolarization. Mechanistically, ALA up-regulated the expressions of G protein coupled receptor (GPR) 120 and associated β-inhibitor protein 2 (β-arrestin2), accompanied by observable weakened levels of transforming growth factor-β activated kinase 1 (TAK1), NF-κB p65, cysteine proteinase-1 (caspase-1), pro-caspase-1, associated speck-like protein (ASC) and NLRP3. In vitro, ALA directly restrained the inflammation of microglia by decreasing the levels of pro-inflammatory factors and regulating microglial polarization via GPR120-NF-κB/NLRP3inflammasome signaling pathway, whereas AH7614 definitely eliminated this anti-inflammatory effect of ALA.

CONCLUSION

Dietary ALA ameliorates microglia-mediated neuroinflammation by suppressing the NF-κB/NLRP3 pathway via binding GPR120-β-arrestin2.

Exploring therapeutic potential: Targeting TRPM7 in neurodegenerative diseases

The ions Ca2+ and Mg2+, which are both present in the body, have been demonstrated to be crucial in the control of a variety of neuronal processes. Transient melastatin-7 (TRPM7) channel plays an important role in controlling Ca2+ and Mg2+ homeostasis, which is crucial for biological processes. The review will also examine how changes in TRPM7 function or expression can lead to neurodegeneration.Even though eight different TRPM channels have been found so far, the channel properties, activation mechanisms, and physiological responses exhibited by these channels can vary greatly from one another. Only TRPM6 and TRPM7 out of the eight TRPM channels were found to have a high permeability to both Ca2+ and Mg2+. In contrast to TRPM6 channels, which are not highly expressed in neuronal cells, TRPM7 channels are widely distributed throughout the nervous system, so they will be the sole focus of this article. It is possible that, in the future, for the treatment of neurodegenerative disorder new therapeutic drug targets will be developed as a direct result of research into the specific roles played by TRPM7 channels in several different neurodegenerative conditions as well as the factors that are responsible for TRPM7 channel regulation.

NR1H4 ameliorates Parkinson's disease via inhibiting astrocyte activation and neuroinflammation in a CEBPβ/NF-κB dependent manner

Parkinson's Disease (PD) is a degenerative disease driven by neuroinflammation. Nuclear receptor subfamily 1 group H member 4 (NR1H4), a nuclear receptor involved in metabolic and inflammatory regulation, is found to be widely expressed in central nervous system. Previous studies suggested the protective role of NR1H4 in various diseases related to inflammation, whether NR1H4 participates in PD progression remains unknown. To investigate the role of NR1H4 in neuroinflammation regulation, especially astrocyte activation during PD, siRNA and adenovirus were used to manipulate Nr1h4 expression. RNA-sequencing (RNA-seq), quantitative real-time PCR, enzyme-linked immunosorbent assay, Chromatin immunoprecipitation and western blotting were performed to further study the underlying mechanisms. We identified that NR1H4 was down-regulated during PD progression. In vitro experiments suggested that Nr1h4 knockdown led to inflammatory response, reactive oxygen species generation and astrocytes activation whereasNr1h4 overexpressionhad the opposite effects. The results of RNA-seq on astrocytes revealed that NR1H4 manipulated neuroinflammation in a CEBPβ/NF-κB dependent manner. Additionally, pharmacological activation of NR1H4 via Obeticholic acid ameliorated neuroinflammation and promoted neuronal survival. Our study first proved the neuroprotective effects of NR1H4against PD via inhibiting astrocyte activation and neuroinflammation in a CEBPβ/NF-κB dependent manner.

Cell-specific spatial profiling of targeted protein expression to characterize the impact of intracortical microelectrode implantation on neuronal health

Intracortical microelectrode arrays (MEAs) can record neuronal activity and advance brain-computer interface (BCI) devices. Implantation of the invasive MEA kills local neurons, which has been documented using immunohistochemistry (IHC). Neuronal nuclear protein (NeuN), a protein that lines the nuclei of exclusively neuronal cells, has been used as a marker for neuronal health and survival for decades in neuroscience and neural engineering. NeuN staining is often used to describe the neuronal response to intracortical microelectrode array (MEA) implantation. However, IHC is semiquantitative, relying on intensity readings rather than directly counting expressed proteins. To supplement previous IHC studies, we evaluated the expression of proteins representing different aspects of neuronal structure or function: microtubule-associated protein 2 (MAP2), neurofilament light (NfL), synaptophysin (SYP), myelin basic protein (MBP), and oligodendrocyte transcription factor 2 (OLIG2) following a neural injury caused by intracortical MEA implantation. Together, these five proteins evaluate the cytoskeletal structure, neurotransmitter release, and myelination of neurons. To fully evaluate neuronal health in NeuN-positive (NeuN+) regions, we only quantified protein expression in NeuN+ regions, making this the first-ever cell-specific spatial profiling evaluation of targeted proteins by multiplex immunochemistry following MEA implantation. We performed our protein quantification along with NeuN IHC to compare the results of the two techniques directly. We found that NeuN immunohistochemical analysis does not show the same trends as MAP2, NfL, SYP, MBP, and OLIG2 expression. Further, we found that all five quantified proteins show a decreased expression pattern that aligns more with historic intracortical MEA recording performance.

Alzheimer's disease-linked risk alleles elevate microglial cGAS-associated senescence and neurodegeneration in a tauopathy model

The strongest risk factors for late-onset sporadic Alzheimer's disease (AD) include the ε4 allele of apolipoprotein E (APOE), the R47H variant of triggering receptor expressed on myeloid cells 2 (TREM2), and female sex. Here, we combine APOE4 and TREM2R47H (R47H) in female P301S tauopathy mice to identify the pathways activated when AD risk is the strongest, thereby highlighting detrimental disease mechanisms. We find that R47H induces neurodegeneration in 9- to 10-month-old female APOE4 tauopathy mice. The combination of APOE4 and R47H (APOE4-R47H) worsened hyperphosphorylated tau pathology in the frontal cortex and amplified tauopathy-induced microglial cyclic guanosine monophosphate (GMP)-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling and downstream interferon response. APOE4-R47H microglia displayed cGAS- and BAX-dependent upregulation of senescence, showing association between neurotoxic signatures and implicating mitochondrial permeabilization in pathogenesis. By uncovering pathways enhanced by the strongest AD risk factors, our study points to cGAS-STING signaling and associated microglial senescence as potential drivers of AD risk.